function showAllPositions(){

	if(ckb_all_selected.checked){
		
		var elementos = document.getElementsByName("ckb_ponto");
		for(var i=0;i< elementos.length;i++){
			
			elementos[i].checked = true;
		} 
		if(dataByDate){
			showAllMarkersByDate();
		}else{
			showAllMarkers();
		}
		
		return true;
		
	}else{	
			
		var elementos = document.getElementsByName("ckb_ponto");
		for(var i=0;i< elementos.length;i++){
			elementos[i].checked = false;
		} 
		if(dataByDate){
			removeAllMarkersByDate();
		}else{
			removeAllMarkers();
		}
		
		return true;
	}

}